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Sheet for a thermal conductive substrate, a method for manufacturing the same, a thermal conductive substrate using the sheet and a method for manufacturing the same

a thermal conductive substrate and thermal radiation technology, applied in the field of circuit substrates, can solve the problems of low break down voltage, large noise, and difficult for metal base substrates and ceramic substrates to meet both performance and cost requirements, and achieve excellent thermal radiation properties

Inactive Publication Date: 2005-03-08
PANASONIC CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

"The present invention provides a sheet for a thermally conductive substrate that can be easily molded and processed into a desired shape, with excellent thermal conductivity and flexibility. The sheet is made of a resin composition comprising at least thermosetting resin, hardener, and hardening accelerator. The sheet can be filled with inorganic filler to form a thermally conductive module. The resulting thermally conductive substrate has excellent mechanical strength and flexibility. The invention also provides a method for manufacturing the sheet and the thermally conductive substrate."

Problems solved by technology

Therefore, as for the substrate of thin insulating layer, break down voltage is low, and the influence by the noise, too, is big.
It is difficult for the metal base substrate and ceramic substrate to satisfy both performance and cost requirements.
However, due to the high viscosity of the thermoplastic resin, it is difficult to injection mold such a module with a high filler content, and so the thermal radiation property of module is poor.
In particular, at the time of melting the thermoplastic resin at high temperature and kneading with filler, if there is too much filler, the melting viscosity is rapidly increased in a point that not only kneading but also injection molding is made impossible.
Moreover, the filler serves as an abrasives to abrade the metallic mold, and, thus, reduces the life of the mold.
Consequently, the content of the filler is limited, so that only lower thermal conductivity can be obtained as compared with the thermal conductivity of the ceramic substrate.

Method used

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  • Sheet for a thermal conductive substrate, a method for manufacturing the same, a thermal conductive substrate using the sheet and a method for manufacturing the same
  • Sheet for a thermal conductive substrate, a method for manufacturing the same, a thermal conductive substrate using the sheet and a method for manufacturing the same
  • Sheet for a thermal conductive substrate, a method for manufacturing the same, a thermal conductive substrate using the sheet and a method for manufacturing the same

Examples

Experimental program
Comparison scheme
Effect test

example 1

In the formation of the thermally conductive sheet of the present invention; inorganic filler, thermosetting resin and solvent were mixed and alumina balls were further added into the above mixture so as to obtain a sufficient dispersion. The compositions of the thermally conductive sheet of this Example are shown in Table 1.

TABLE 1Thermosetting resinSolvent having aSheet(includingboiling point ofOther after driedExperimentInorganic Fillerhardener)not more than 150° C.additivesViscosityNo.NameVol. (wt %)NameVol. (wt %)NameVol. (wt %)*1*2*3(Pa · s)1aAl2O360Epoxy36Butyl4———1.5 × 102resincalbitol1bAl2O370Epoxy28acetate2———3.3 × 103resin(BCA)1cAl2O380Epoxy182———2.6 × 104resin1dAl2O390Epoxy9.50.5———8.1 × 104resin1eAl2O395Epoxy4.90.1———1.3 × 105Resin*1: coloring agent *2: coupling agent *3: dispersing agent

Table 1 shows an evaluation of the performance of the thermally conductive sheet when the content of Al2O3 as an inorganic filler is changed. As Al2O3, “AL-33” having a particle diamet...

example 2

In this Example, a thermally conductive substrate in which the thermally conductive sheet was manufactured by the same method as in Example 1 and integrated with a lead frame will be explained. The compositions of the thermally conductive sheet used in this Example will be described hereinafter.(1) Inorganic filler: 90 weight % of Al2O3, “AS-40®” (the product of SHOWA DENKO K.K.) having a spherical shape and an average particle size of 12 μm.(2) Thermosetting resin: 9 weight % of cyanate ester resin, “AroCy M30®” (the product of Asahi-Ciba CO., Ltd.)(3) Solvent having a boiling point of not less than 150° C.: 0.5 weight % of butyl carbitol. (the first grade of chemical reagent of Kanto Chemical CO, Inc.).(4) Other additives: 0.3 weight % of “Carbon Black” (the product of Toyo-carbon CO., Ltd.), and 0.2 wt. % of dispersing agent, “PLYSURF F-208F®” (the product of DAI-ICHI SEIYAKU KOGYO CO., LTD.).

A thermally conductive sheet (a thickness was 770 μm) comprising the above mentioned com...

example 3

In this Example, a thermally conductive substrate will be explained, where the thermally conductive sheet was manufactured by the same method as in Example 1 and both sides of the sheet had metallic foil wiring layers and conductive resin composition was filled between the layers to electrically connect the layers. The compositions of the thermally conductive sheet used in this Example will be described hereinafter.(1) Inorganic filler: 90 weight % of Al2O3, “AS-40®” (the product of SHOWA DENKO K.K.) having a spherical shape and an average particle size of 12 μm.(2) Thermosetting resin: 9 weight % of “NRV-1010®” (the product of Japan REC CO., Ltd.), a mixture comprising 60 weight parts of brominated multifunctional epoxy resin as a main agent, 39.5 weight parts of bisphenol A nobolak resin as a hardener, and 0.5 weight parts of imidazol as a hardening accelerator.(3) Solvent having a boiling point of not less than 150° C.: 0.5 weight % of butyl carbitol (the first grade chemical rea...

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Abstract

A thermally conductive substrate having a structure in which inorganic filler for improving the thermal conductivity and thermosetting resin composition are included. The thermosetting resin composition has a flexibility in the not-hardened state, and becomes rigid after hardening. The thermally conductive substrate has excellent thermal radiation characteristics. The method of manufacturing the thermally conductive substrate includes: piling up (a) the thermally conductive sheets comprising 70 to 95 weight parts of an inorganic filler, and 4.9 to 28 weight parts of a thermosetting resin composition, the thermosetting resin composition comprising at least one thermosetting resin, a hardener and a hardening accelerator, and (b) lead frame on which a wiring is formed; thermal pressing the pile; filling the thermally conductive sheet to the surface of the lead frame; hardening the thermosetting resin; cutting excess sections of the thermally conductive substrate; and processing the bending perpendicularly for making a removable electrode.

Description

FIELD OF THE INVENTIONThe invention relates to a circuit substrate whose thermal radiation property is improved by a mixture of resin and inorganic filler. In particular, it relates to a high thermal radiation printed wiring board made of resin (thermally conductive substrate) for mounting electronic power devices.BACKGROUND OF THE INVENTIONRecently, as high performance and miniaturization of the electronic apparatus have been required, high density and high performance semiconductors have been sought. Consequently, circuit substrates for mounting thereof have also been required to be small and of high density. As a result, it is important to design circuit substrates taking the thermal radiation property into consideration. A well known technique for improving the thermal radiation property of circuit substrates, while using a printed circuit board made of glass-epoxy resin, is to use, a metal base substrate having a metal, for example, aluminum etc. and form a circuit pattern on o...

Claims

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Application Information

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Patent Type & Authority Patents(United States)
IPC IPC(8): B32B15/08H01L23/14H01L23/498H01L23/12H01L23/48H05K1/03H05K3/00H05K3/40H05K3/20H05K3/46H05K1/05
CPCB32B15/08H01L23/49833H01L23/49861H05K1/0373H01L23/145Y10T156/1034H01L2924/3011H05K1/056H05K3/0058H05K3/202H05K3/4069H05K3/4092H05K3/4614H05K3/4652H05K2201/0209H05K2201/0355Y10S428/901H01L2924/0002Y10T428/252Y10T428/265Y10T428/257Y10T428/24917Y10T156/1092Y10T428/258Y10T156/109Y10T428/25Y10T156/1056Y10T156/1057H01L2924/00Y10T428/31681Y10T428/31692B32B2311/12B32B2307/302B32B2305/74B32B27/20B32B2457/08
Inventor NAKATANI, SEIICHIHANDA, HIROYUKI
Owner PANASONIC CORP
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